|
A research team led by University of Hawaii oceanographer Jim Cowen discovered living organisms in an unprecedented investigation of the deep ocean crust. UH researchers find life
buried under ocean crustBy Helen Altonn
haltonn@starbulletin.com
They discovered microscopic life in fluids of 3.5-million-year-old ocean crust buried under deep sediments. The fluids were 149 degrees, which Cowen said is beyond the temperature range tolerated by most organisms found at the surface of the earth and ocean.
Reporting their findings in the Jan. 3 issue of Science magazine, the scientists said, "The possibility of a biosphere (with living organisms) extending throughout the immense volume of aging crust under the global system of mid-ocean ridge flanks and ocean basins is controversial."
Cowen said, "There was suspicion among many of us that there might be some (microbial) growth."
He added, "It might be very slow growth or a low level of activity, but the tremendous volume of ocean crust could translate a very small, very slow activity level into a significant global process."
The researchers drilled a 990-foot borehole on the flanks and other sites of Juan de Fuca Ridge.
The borehole was fitted with a sampling device called the Circulation Obviation Retrofit Kit, or CORK, owned by the U.S. Ocean Drilling Program, enabling them to reach fluids normally inaccessible for studies.
Genes cloned from collected organisms revealed a diverse collection of bacteria and archaea (microorganisms found in extreme environments), the scientists reported.
Cowen said some organisms recovered are relatives of those found in hypothermal environments, including one closely related to microorganisms found only in hot-spring vents at Yellowstone National Park.
Others may be different species of life that adapted to very high temperatures of deep ocean crust, he said.
He said the ocean crust is "a huge new frontier" that scientists know little about.
"Any time you can demonstrate there is a new, significant microbial or biological process, it is inherently interesting and important," he said.
He said the chemistry of the deep crustal fluids "was conducive to microbial activity of a number of known thermophiles and hyperthermophiles."
Thermophiles are organisms that grow in high temperatures and hyperthermophiles in even higher temperatures.
Moving away from the mid-ocean ridges, Cowen said, the temperature of the crustal fluids increases to 212 degrees from 35 degrees.
"We now know that is a very comfortable temperature range for a diverse population of microorganisms," he said.
The field work was done in 1998 and 1999 with two research ships, the Thomas G. Thompson operated by the University of Washington, and the Atlantis operated by Woods Hole Oceanographic Institution.
Woods Hole's remotely operated vehicle Jason and submersible Alvin were used for dives.
Cowen said funds will be requested from the National Science Foundation to conduct experiments at the site, as close to the crustal environment as possible.
The researchers also want to isolate organisms, raise them in culture "and test them for what they can do," he said.
Science magazine
UH Oceanography